/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 * Loader.java
 * Copyright (C) 2005 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.gui;

import java.io.Reader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;

/**
 * This class is for loading resources from a JAR archive.
 * 
 * @author FracPete (fracpete at waikato dot ac dot nz)
 * @version $Revision: 1.2 $
 */

public class Loader {
	/**
	 * the dir to use as prefix if filenames are w/o it, must have a slash at
	 * the end (the path separator is a slash!)
	 */
	private String dir;

	/**
	 * initializes the object
	 */
	public Loader(String dir) {
		this.dir = dir;
	}

	/**
	 * returns the dir prefix
	 */
	public String getDir() {
		return dir;
	}

	/**
	 * returns the processed filename, i.e. with the dir-prefix if it's missing
	 */
	public String processFilename(String filename) {
		if (!filename.startsWith(getDir()))
			filename = getDir() + filename;

		return filename;
	}

	/**
	 * returns a URL for the given filename, can be NULL if it fails
	 */
	public static URL getURL(String dir, String filename) {
		Loader loader;

		loader = new Loader(dir);
		return loader.getURL(filename);
	}

	/**
	 * returns a URL for the given filename, can be NULL if it fails
	 */
	public URL getURL(String filename) {
		filename = processFilename(filename);
		return Loader.class.getClassLoader().getResource(filename);
	}

	/**
	 * returns an InputStream for the given dir and filename, can be NULL if it
	 * fails
	 */
	public static InputStream getInputStream(String dir, String filename) {
		Loader loader;

		loader = new Loader(dir);
		return loader.getInputStream(filename);
	}

	/**
	 * returns an InputStream for the given filename, can be NULL if it fails
	 */
	public InputStream getInputStream(String filename) {
		filename = processFilename(filename);
		return Loader.class.getResourceAsStream(filename);
	}

	/**
	 * returns a Reader for the given filename and dir, can be NULL if it fails
	 */
	public static Reader getReader(String dir, String filename) {
		Loader loader;

		loader = new Loader(dir);
		return loader.getReader(filename);
	}

	/**
	 * returns a Reader for the given filename, can be NULL if it fails
	 */
	public Reader getReader(String filename) {
		InputStream in;

		in = getInputStream(filename);

		if (in == null)
			return null;
		else
			return new InputStreamReader(in);
	}
}
